There are several ways to do that. If you look for a portable way
(I mean it will work on all Unix machines and also WinsowsNT)
look at the source of the h2root (Hbook -->Root) conversion
program.
This program reads a ZebraRZ structure via calls to Hbook/Zebra
routines and access the Q,IQ,LQ in the C++ code.
The source of h2root can be found in the standard Root source
distribution file on the Web.
In the root/src directory, look for the file
UTILS_h2root.cxx
Rene Brun